Heat dissipation device

ABSTRACT

A heat dissipation device includes a base, a sleeve coupling with the base, and a fastener engaging with the base and the sleeve. The base defines a hole extending therethrough. The sleeve includes a first portion coupling with the hole of the base and a second portion extending from an end of the first portion. The second portion is located at a first side of the base. The fastener includes a body portion extending through the sleeve and the base, a head portion and a foot portion formed at two ends of the body portion, respectively. The head portion is located at the first side of the base. A spring member is compressed between the head portion and the second portion. A compressed length of the spring member is adjustable by adjusting a coupling length of the first portion with the hole of the base.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat dissipation device, and particularly to a heat dissipation device with a fastener for fastening the heat dissipation device to an electronic device.

2. Description of Related Art

It is well known that, during operation of a computer, electronic devices such as central processing units (CPUs) frequently generate large amounts of heat. The heat must be quickly removed from the electronic device to prevent it from becoming unstable or being damaged. Typically, heat dissipation device including a heat sink is attached to an outer surface of the electronic device to absorb heat from the electronic device. The heat absorbed by the heat sink is then dissipated to ambient air.

In order to keep the heat sink in intimate contact with the electronic device, the heat dissipation device includes a fastener engaging with a printed circuit board where the electronic device is located to fasten the heat sink to the electronic device. Generally, the heat sink comprises a base defining a through hole therein. The fastener comprises a pole portion, a head portion extending from an end of the pole portion and an engaging portion extending from another end of the pole portion for engaging with the printed circuit board. A spring circles the pole portion. When fastening the heat sink to the electronic device, the engaging portion of the fastener extends through the through hole of the base of the heat sink and a corresponding aperture of the printed circuit board to engage with a back plate located at a bottom side of the printed circuit board. The spring is compressed between the base and the head portion of the fastener and presses the heat sink to the electronic device. However, when the engaging portion engages with the back plate, a compressed length of the spring is invariable; thus, a spring force produced by the compressed spring is invariable and can not be adjust to meet different electronic devices or a same electronic device under different circumstances with different pressure requirements.

What is needed, therefore, is a heat dissipation device capable of producing a fastening force which is adjustable to meet different requirements.

SUMMARY OF THE INVENTION

The present invention relates to a heat dissipation device. According to a preferred embodiment of the present invention, the heat dissipation device comprises a base, a sleeve coupling with the base, and a fastener engaging with the base and the sleeve. The base defines a thread hole extending therethrough. The sleeve comprises a first portion coupling with the hole of the base and a second portion extending upwardly from an end of the first portion. The second portion is located at a first side of the base. A through hole extends through the sleeve. The fastener comprises a body portion extending through the through hole of the sleeve, a head portion extending upwardly from an end of the body portion, a foot portion extending downwardly from another end of the body portion. The head portion is located at the first side of the base. The foot portion is located at a second side of the base. A spring member is compressed between the head portion and the second portion of the sleeve. A compressed length of the spring member is capable of being varied by adjusting a coupling length of the first portion of the sleeve with the thread hole of the base.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an isometric, exploded view of a heat dissipation device in accordance with a preferred embodiment of the present invention.

FIG. 2 shows a fastener and a sleeve of the heat dissipation device of FIG. 1.

FIG. 3 is a partially assembled view of FIG. 1.

FIG. 4 is an assembled view of FIG. 1.

FIG. 5 is a left side view of FIG. 4.

FIG. 6 is a left side view of FIG. 4, wherein the sleeve of the heat dissipation device is threaded in to move downwardly a distance, in comparison with the sleeve of the heat dissipation device in FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a heat dissipation device of a preferred embodiment is shown. The heat dissipation device comprises a heat sink 10, two fasteners 20 for fastening the heat sink 10 to an electronic device (not shown) mounted on a printed circuit board (not shown) and two sleeves 25 engaging with the heat sink 10 and the fasteners 20 for adjusting fastening force of the fasteners 20 to the heat sink 10.

The heat sink 10 comprises a base 11, a fin set 15 arranged on the base 11 and four heat pipes 18 connecting the base 11 and the fin set 15. The base 11 is a substantially rectangular plate having good heat conductivity. The base 11 defines two thread holes 112 in middles of two lateral opposite portions thereof. The base 11 defines four parallel grooves 118 for receiving the heat pipes 18. A cutout 115 is defined in a front side of the base 11, adjacent to front ends of the four grooves 118. The fin set 15 comprises a plurality of fins 151 assembled together. Each of the fins 151 extends a top flange (not labeled) and a bottom flange (not labeled) from top and bottom edges thereof. The bottom flanges of the fins 151 interconnect one by one to form a flat bottom face (not labeled) contacting the base 11. The fin set 15 defines two cutouts 153 corresponding to the thread holes 112, which avoid interference between the fin set 15 and the fasteners 20 when the fasteners 20 are used to secure the heat sink 10 to the printed circuit board. The fin set 15 defines four receiving slots 158 extending through each fin 151 of the fin set 15. The four slots 158 radially extend from a middle of the bottom face of the fin set 15 toward a top portion of the fin set 15. The four slots 158 have converged bottoms and diverged tops. The bottoms of the four slots 158 are opened to and in communication with corresponding grooves 118 of the base 11.

Each heat pipe 18 comprises an evaporating section (not labeled), a condensing section (not labeled) parallel to the evaporating section, and a connecting section (not labeled) connecting the evaporating section and the condensing section. The evaporating sections of the heat pipes 18 are received in the corresponding grooves 118 of the base 11 and the bottoms of the slots 158 of the fin set 15. The evaporating sections of the heat pipes 18 are parallel to each other and converged in the base 18 and the bottom of the slots 158. The condensing sections of the heat pipes 18 are parallel to each other and received in the tops of the slots 158 of the fin set 15. The connecting sections of the heat pipes 18 extend from the bottoms to the tops of the slots 158 of the fin set 15.

Referring also to FIG. 2, each fastener 20 comprises a shaft member 21 and a helical spring 23 circling the shaft member 21. The shaft member 21 is integrally made of plastic or metal material. The shaft member 21 comprises a body portion 210, a head portion 212 formed at a top end of the body portion 210, and a foot portion 218 formed at an opposite bottom end of the body portion 210. The head portion 212 has a diameter larger than that of the body portion 210. The body portion 210 has the diameter larger than that of the foot portion 218. The head portion 212 defines an operating groove (not labeled) for facilitating operation of a tool such as a screwdriver to fasten the heat dissipation device to the printed circuit board. The body portion 210 defines a circumferential groove on a periphery thereof, thereby forming a locking portion 214 with a diameter less than that of the body portion 210. The locking portion 214 is adjacent to the foot portion 218.

The sleeve 25 is a one-piece member and comprises an abutting portion 250 and a thread portion 255 extending downwardly from a bottom end of the abutting portion 250. A through hole 258 extends through the abutting portion 250 and the thread portion 255. In this embodiment, the abutting portion 250 has a regular-hexagonal-prism profile. The abutting portion 250 has a flat top face (not labeled) for supporting the spring 23. The thread portion 255 has a cylinder profile. The thread portion 255 is machined with a plurality of threads on a circumferential periphery thereof, for coupling with the thread hole 112 of the base 11. The through hole 258 has an upper portion surrounded by the abutting portion 250 and having a hexagonal profile, and a lower portion surrounded by the thread portion 255 and having a cylindrical profile.

Referring also to FIGS. 3-5, when the heat sink 10 is assembled to the electronic device on the printed circuit board, the heat sink 10 seats on the electronic device. The sleeves 25 engage with the base 11 of the heat sink 10 by the thread portions 255 of the sleeves 25 coupling with corresponding thread holes 112 of the base 11. The fasteners 20 have the foot portions 218 inserted into corresponding through holes 258 of the sleeves 25 and extending downwardly beyond the thread holes 112 of the base 11. The locking portions 214 of the fasteners 20 extend downwardly beyond the base 11. A collar 27 allows the body portion 210 to extend therethrough and snaps with the body portion 210 in the locking portion 214 of each of the fasteners 20. The collar 27 is therefore located under the base 11.

The foot portions 218 further extend through corresponding through apertures defined in the printed circuit board and engage with a back plate located under the printed circuit board. Here, as shown by FIG. 5, the spring 23 between the head portion 212 of the shaft 21 and the abutting portion 250 of the sleeve 25 is compressed by a distance. The compressed spring 23 produces a fastening force on the abutting portion 250 and presses the base 11 toward the electronic device. Therefore, the heat sink 10 is intimately fastened to the electronic device on the printed circuit board.

Referring also to FIG. 6, when the electronic device requires a smaller fastening force produced by the compressed spring 23, the thread portion 255 of the sleeve 25 is further threaded into the thread hole 112 of the base 11. By this manner, a coupling length of the thread portion 255 and the thread hole 112 of the base 11 is increased, the spring 23 between the head portion 212 of the fastener 20 and the abutting portion 250 of the sleeve 25 is expanded, in comparison with FIG. 5, and the compressed distance of the spring 23 is decreased, whereby the spring 23 produces a smaller fastening force on the abutting portion 250 and the base 11 toward the electronic device, in comparison with the fastener 20 in the state of FIG. 5. So the electronic device has a smaller engaging force acting thereon by the heat sink 10.

It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention. 

1. A heat dissipation device comprising: a base defining a hole extending therethrough; a sleeve coupling with the hole of the base, a through hole extending through the sleeve; a fastener comprising a body portion extending through the through hole of the sleeve, a head portion extending upwardly from an end of the body portion, a foot portion extending downwardly from another end of the body portion, a spring member being compressed between the head portion and the sleeve, a compressed length of the spring member capable of being varied by adjusting a coupling length of the sleeve with the hole of the base.
 2. The heat dissipation device of claim 1, wherein the hole of the base is a thread hole, and the sleeve comprises a thread portion engaging in the thread hole of the base.
 3. The heat dissipation device of claim 2, wherein the sleeve comprises an abutting portion extending upwardly from an end of the thread portion and located at a side of the base, the spring member being compressed between the head portion of the fastener and the abutting portion.
 4. The heat dissipation device of claim 3, wherein the abutting portion of the sleeve has a flat face supporting the spring member.
 5. The heat dissipation device of claim 3, wherein the abutting portion of the sleeve has a regular-hexagonal-prism profile.
 6. The heat dissipation device of claim 1, wherein the foot portion of the fastener is machined with a plurality of threads thereon.
 7. The heat dissipation device of claim 1, wherein the body portion of the fastener defines an annular groove therein to form a locking portion between the head portion and the foot portion, the locking portion being located at another side of the base, a collar snapping with the body portion at the locking portion.
 8. The heat dissipation device of claim 1, wherein the spring member is helical and circles the body of the fastener.
 9. The heat dissipation device of claim 1, wherein the foot portion of the fastener has a diameter less than that of the body portion.
 10. A heat dissipation device comprising: a base; a sleeve having a first portion engaging with the base and a second portion located at a first side of the base; a fastener comprising a head portion located at the first side of the base, a body portion extending through the sleeve and the base, and a foot portion located at a second side of the base, a spring member being compressed between the head portion and the second portion of the sleeve, a compressed length of the spring member capable of being adjusting by adjusting a coupling length of the first portion of the sleeve with the base.
 11. The heat dissipation device of claim 10, wherein the base defines a thread hole, the second portion of the sleeve is machined with threads at a periphery thereof, the threads engaging with the thread hole.
 12. The heat dissipation device of claim 10, wherein the second portion of the sleeve has a flat face supporting the spring member.
 13. The heat dissipation device of claim 12, wherein the second portion of the sleeve has a regular-hexagonal-prism profile.
 14. The heat dissipation device of claim 10 further comprising a fin set, wherein the fin set is arranged on the base.
 15. The heat dissipation device of claim 14 further comprising a plurality of heat pipes connecting with base and the fin set, wherein each of the heat pipes comprises an evaporating section located between the base and the fin set, and a condensing section remote from the base and contacting the fin set.
 16. The heat dissipation device of claim 15, wherein the fin set defines a plurality of slots radially extending from a bottom of the fin set toward a top of the fin set, the evaporating sections of the heat pipes being received in bottom ends of the slots, the condensing sections of the heat pipes being in top ends of the slots.
 17. The heat dissipating device of claim 16, wherein the base defines a cutout in a side thereof, corresponding to ends of the evaporating sections of the heat pipes.
 18. The heat dissipation device of claim 14, wherein the fin set defines a cutout corresponding to the fastener. 